Bio:Keiko Ishikawa O'Brien is the wife of Miles Edward O'Brien, and the mother of Molly and Yoshi O'Brien. When introduced on Star Trek: The Next Generation, Keiko was a (possibly civilian) botanist on board the USS Enterprise-D.

Several members of the main cast of TNG have had significant contact with Keiko. For instance, it was Data who introduced Keiko to Miles. During the consequent wedding, he acted as the "father" of the bride, and gave her away to Miles. Captain Picard performed the wedding ceremony. Worf delivered Molly and has long held a special relationship with the O'Brien children that continued on Deep Space Nine. Indeed, he was Yoshi's first babysitter.

When the O'Briens moved to DS9, Kieko found herself at in professional distress. Botany played an extremely limited role in the day-to-day operations of the space station. For a time, she and Miles went through a difficult time which threatened to dissolve her marriage. However, she managed to found a productive role for herself by taking on board the responsibility of running a school for the children of DS9. When that school was later disbanded, she reached a compromise with Miles, whereby she became a sort of "freelance" botanist — sometimes working for the Bajoran government, sometimes the Federation. Her assignments would take her away from DS9 for months at a time.

Thus she is effectively a semi-regular member of the cast who will appear from time to time as the stories warrant, with her absences causing no great continuity errors.